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NMSU professor finding ways to remove organic pollutants in water

An assistant professor in New Mexico State University’s Department of Chemical & Materials Engineering recently received a $373,000 grant from NASA and a $50,000 grant from the National Science Foundation for research to remove pollutants from groundwater using local waste materials.

New Mexico State University chemical engineering Assistant Professor Catherine Brewer holds cups of pecan shells, left, and activated-carbon pecan shells. (NMSU photo by Billy Huntsman)
Catherine Brewer, New Mexico State University chemical engineering assistant professor, stands next to the burner used to burn the pecan shells, activating the carbons required to remove carcinogenic NDMA from the underground water at White Sands Test Facility. (NMSU photo by Billy Huntsman)

Catherine Brewer’s three-year NASA grant is for research pertaining to the absorption of N-Nitrosodimethylamine (NDMA) from the water beneath the White Sands Test Facility.

“NDMA is a probable human carcinogen,” Brewer said. “In the 1960s and ‘70s, NASA tested a series of rocket fuels for the Apollo program at the WSTF. After each test, the test engine and fuel lines had to be cleaned and flushed. The wastewater from those flushes was treated to remove the fuel compounds and then emptied into the desert.”

Unbeknownst to the scientists, the treatment process to destroy the fuel residues created NDMA in the water, Brewer said.

“In the 1980s, NASA became aware of the NDMA and other organic pollutants in the water underneath WSTF,” Brewer said. “Since then, they have been pumping up the water, treating it by air stripping to remove the NDMA and re-injecting it underground.”

Brewer said the treatment process will likely need to be continued over the next century with thousands of gallons per day, requiring much electricity and costing a great deal.

“The purpose of this project is to see if we can make pecan shells with activated carbons that can adsorb the NDMA out of the water as effectively but for a lower cost,” Brewer said.

Brewer said the project started two years ago and is currently in the analytical stage – measuring NDMA concentrations in water at the part per trillion level.

“After that, the remaining time of the three-year project will be spent designing the adsorption water treatment system using pecan shells with activated carbons,” Brewer said.

The NSF grant is for Brewer to research burning bio-waste, such as pecan shells, pecan orchard prunings, cotton gin trash and yard waste, to create heat in order to desalinate brackish water.
Using heat generated from bio-waste can reduce the effects of scaling, a common problem when desalinating water, especially in this region, Brewer said.

In addition to these two projects, Brewer has also been the principal investigator for five other projects, funded by the Sun Grant Program South Central Region, the NM WRRI-Bureau of Reclamation Cooperative Agreement, the Western Excelsior Corporation, NASA and the USDA. These five projects have received more than $574,000 in funding.

“On every project, I have worked with researchers from multiple colleges, multiple institutions and industry,” Brewer said. “As a land-grant institution, NMSU is well-suited for this kind of research as it is easy to pull together the needed expertise from basic science, applied agricultural science, engineering and extension. I am very grateful for the wonderful collaborators I have found here.”